Lock-out box and shunt-circuit for telephone-exchanges



(No Model.) 2 Sheets-Sheet 1. 0. H. HASKINS.

v LOCK OUT BOX AND SHUNT CIRCUIT FOR TELEPHONE EXCHANGES. r No. 378,679.Patented Feb. 28,1888.

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(No Model.) 2SheetsSheet 2, O. H. HASKINS.

LOOK OUT BOX AND SHUNT CIRCUIT FOR TELEPHONE EXGHANGE8.

No. 378,679. Patented Feb. 28, 1888.

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IINiTnn STATES IFFTCE.

PATENT CHARLES H. IIASKINS, OF MILWAUKEE, ,WVISCONSIN, ASSIGNOR TO THE\VESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS.

LOCK-OUT BOX AND SHUNT-CIRCUIT FOR TELEPHONE-EXCHANGES.

SPECIFICATION forming part of Letters Patent No. 378,679, dated February28, 1888.

I Application filed December 3, 1885. Serial No. 184,562. (No model.)

To all whom it may concern:

Be it known that I, CHARLES H. HASKINS, a citizen of the United States,residing at Milwaukee,in the county of Milwaukee and State of Wisconsin,have invented a certain new and useful Improvement in LockOut Boxes andShunt-Circuits for Telephone-Exchanges, of which the following is afull, clear, concise,

and exact description, reference being had to the accompanying drawings,forming apart of this specification.

In certain cases it has been found desirable to place two or morestations upon the same line, each station being provided with atelephone, a transmitter, a bell, and generator.

Bliss clocks and other systems of individual calls have been used, sothat one subscriber might be rung up Without disturbing any othersubscriber on the line.

My invention herein relates to the appara tus for use at the stations ofthe different subscribcrs where several subscribers are thus placed uponthe same line.

My invention has for its object,first, to provide a locking device ateach of the stations,by means of which the telephones of all thestations upon a given line,except the station that is first connectedfor conversation, may be excluded from the circuit; and, second, toprovide a shunt-circuit around the boxes of the stations which are thuslocked out, in order that all unnecessary resistance may be removed fromthe talking-circuit.

By the use of my invention any two subscribers of the exchange connectedtogether may hold private conversation with one another withoutliability of interruption by calls from any other subscriber upon theircircuit, while at the same time all unnecessary resistance is removedfrom their circuit.

My invention may be used in connection with the Bliss clock or any otherwell-known individual call. I have illustrated, however, only ordinarykeys for sending signals from the central office over the lines. Thecircuits of the bell and telephone at the different stations are thewell-known open or make-andbreak circuits. IVhen the telephone is hungon the switch, the bell is in circuit and the telephone cut out. Onremoving the telephone the telephone is brought into circuit and thesubscribers upon different lines connected together through the centraloffice for conversa tion, the central-office apparatus being shownsomewhat in detail.

Upon line a are shown three subscribers stations, 1, 2, and3. Upon lineb is shown station at. Stations 2 and 4 are shown connected togetherthrough a pair of cords, said cords id cluding a clearingout shutter cand battery (Z. \Vhen two subscribers are thus connected together, othersubscribers on the same-lines, as subscribers l and 3, will be lockedont,so that they cannot ring or listen. 7 5

As shown in Figs. 1 and 2, electro-magnet e of the locking and shuntingmechanism is permanentlyincluded in the circuit of the telephone-line.When battery (I is included in a line, all electromagnets e of thecircuit will be energized, and all the subscribers upon the circuit,except the two that are in communication,will be locked out, as beforestated, and ashunt-circuitwill be closed around the boxes that are thuslocked out, as indicated in Fig. 8 5 2. When magnet e is energized, thepivoted lever e, which is linked to the armature of said electro-magnet,is brought into the position shown under and in the path of the innerend of the switch-lever. If, now, the telephone 0 should be removed, themotion of the lever would be arrested by the lever e, as shown. Thelever 6, when raised to the position shown, comes in contact with theswitch-1ever,or preferably with thespring-contactf, as shown in 5 Figs.1 and 2. This contact closes the shunt around the generator and bell ofthe box and prevents current from the generator being sent to line,while at the same time the resistance of the bell and generator isshunted out roe of circuit. The spring f, (shown upon the switc'hleverin Fig. 1,) serves as an electrical connection between thetelephone-switch and the stop. Thus when circuit through anyelectro-magnet e is closed the shunt-circuit y will be closedautomatically-that is, at the same time and by the same meansaround thebox, as shown in Fig. 2, and thus as long as current remains upon theline the switch-lever cannot rise to the position indicated by dottedlines in Fig. 1, in which position the bell is disconnected from and thetelephone connected into the circuit of the line.

I will now describe the operation of my system.

Suppose subscriber 2 wishes to talk with subscriber 4. He first sendscurrent, by means of his generator, over his line, thereby throwing downshutter h in line a at the central of fice. The operator, seeing theshutter fall, inserts a plug, i, of a pair of cords in the switch oftheline, as shown. By throwing down the cam-lever 7a, or by means of anyother wellknown switch, theoperator brings his telephone Z into thecircuit, and subscriber 2 thereupon tells the operator that he wantssubscriber 4. The operator at once inserts the other plug, m, of thepair in the spring-jack of line b, as shown. By means of key a. thecalling-battery is thrown upon line b, thus ringing up subscriber 4.Then by throwing up the cam-lever z to the position shown telephone Z isdisconnected from the circuit of the lines, and the said lines areconnected together through the pair of cords, clearing out shutter c andbattery d, as shown. Subscribers 2 and 4 are thus placed in secretcommunication, all other stations on the lines, as stations 1 and 3,being locked out, and the bells of these stations are shunted. Beforethe final connection is made as above described the operator shouldassure himself that subscriber 4 has taken down his telephone, otherwisesubscriber 4 might be locked out of the circuit. The clearing outannunciator c which I have shown is what is known as the closed-circuitannunciator, so arranged that the shutter will be held up as long as thecircuit is closed. The subscriber, on hanging up his telephone, changesthe circuit from his telephone to his bell, as is usual. The circuit ofthe line is thus momentarily opened as the switch passes from one pointto the other, and the shutter falls, whereupon the operator pulls outthe plugs and disconnects the lines. The battery 01 is thus disconnectedfrom the line. The elcctro-magnets e are thus demagnetized, the pivotedlevers 6' fall, and theboXes resume their normal position.

Prior to my invention an electro-magnet had been placed at each of thedifferent subscribers stations of the telephonelines, and so arrangedthat the switches at stations not connected could be locked out bycurrent sent from the central office. Such a system is described inPatent No. 251,178, granted to Charles E. Buell December 20, 1881, fortelephone switch devices. In Buells system, however, no shunt isemployed and the circuits are liable to be left open when locked out.

Having thus described my invention,I claim as new and desire to secureby Letters Pat- (int- An electro-magnet in the circuit of atelephone-line, a telephone-switch, shunt-circuit 9 around the bell andgenerator, a circuit-closiug device. operated by the armature of saidelectro-magnet,and a battery at the central office included in thecircuit, whereby the shuntcircuit may be closed around the box,substantially as and for the purpose specified.

In witness whereof I hereunto subscribe my name this 28d day ofNovember, A. D. 1885.

CH. H. HASKINS. Witnesses:

S. G. LAPHAM, GEo. H. RUssELL.

